You might want to post this in Myrtle Beach forum. Our kid was at least 3 when we went there but he enjoyed beach / pool the most. There is not much in terms of kids stuff otherwise. Children museum is very small. Aquarium is quite expensive and might not be of much interest at such age. No good parks to speak of.
Check Yelp for restaurants. Our kid loved IHOP.
They also have Mellow Mushroom and many restaurants in Broadway at the Beach complex. Usually we rent a condo and do our own cooking. Can't say we were impressed with any of the restaurants. The seafood buffet was awful and overpriced.
Note that many attractions are seasonal and don't open till Memorial Day.